In my prior application, Ser. No. 08/437,991, filed May 10, 1995, now U.S. Pat. No. 5,622,697, a method for inhibiting ammonia volatilization in animal manure, particularly poultry litter for long time periods (3-6 weeks) is disclosed. The method comprises the steps of adding alum (aluminum sulfate) to poultry litter (comprising poultry manure, bedding material, spilled food and feathers) and mixing. In accordance with this application, alum is added in sufficient quantities to reduce the pH of alum/poultry litter base composition to less than 7.0, and preferably, alum may be added a rate of 5% to about 25% by weight based on manure.
In my second above-mentioned patent application, Ser. No. 08/735,103, filed Oct. 22, 1996, a method for rearing animals, including, for example, laying hens, is described wherein animals are raised in a so-called high-rise facility including a raised perforated animal rearing platform and a lower manure collection area. In accordance with the method described in this application, a liquid alum solution is delivered to the manure collection area and sprayed onto a surface of the collected manure to improve, inter alia, the atmospheric conditions of the animal rearing area. In an embodiment of the method described in this latter application, the alum solution, containing from about 1 to about 50% by weight alum, is applied at a rate of about 50 to about 250 g of Al.sub.2 (SO.sub.4).sub.3 H.sub.2 O per kg of manure as it accumulates.
In the present application, a new and improved method is provided including the step of adding alum to poultry litter or manure, wherein the alum is mixed with the surface portion or layer of the poultry litter or manure, for example to a surface depth of from about 0 to about 10 cm. Using this procedure, the amount of alum needed to reduce ammonia volatilization can be dramatically reduced, particularly if the user is only interested in controlling ammonia volatilization for short time periods (days to weeks). The lowest rate of alum addition needed to reduce ammonia volatilization using this technique is about 0.5%, rather than 5%.